170 



DEPARTMENT OF THE NAVAL SERVICE 



Genus Abietinaria. 

 Trophosome. Hydro thecae altei-nate, flask-sliaped, aperture small; operculum 

 with a single adcauline flap. 



Gonosome. Gonangia without spines or internal marsupinm. 



KEY TO SPECIES. 



a Much more than one-third of the hydrothecfe free. 

 h Stem stout. 

 hh Stem slender, i 



Abietinaria ahietina (Linnaeus). 



Trophosome. Main stem stout, straight or slightly 

 flexuous; branches stout, pinnately arranged; hydro- 

 thecae large, broad at the base, tapering to a distinct 

 neck and expanding again slightly to the round, entire 

 margin; much of the hydrotheca, often more than one- 

 half, free from the stem. 



Gonosome. Gonangia oval, with a short collar and 

 wide aperture; surface smooth or slightly annulated. 



Abietinaria filicula (Ellis and Solander). 



Trophosome. Stem slender, straight proximally, 

 flexuous in the branched portion; branches regularly 

 pinnate, often branched again and sometimes the 

 secondary branches are branched; hydrothecse sub- 

 opposite, shaped like those of A. ahietina but much 

 smaller. 



Gonosome. Gonangia oval, tapering to a ne'ck 

 above, with narrow aperture; surface smooth. 



A. ahietina. 

 A. filicula. 



No. 7S. 

 .1 bietinaria abietina. 



No. 79. 

 Abiftinaria filicula. 



Genus Dipiiasia. 



Trophosome. Hydrotheca; in two rows on the stem and branches; operculum of 

 a single adcauline flap. 



Gonosome. Gonangia provided with spines or lobes; an internal marsupium 

 usually present in the female. 



KEY TO SPECIES. 



a Less than one-third of the hydrothecse free. B. fallax. 

 b More than one-third of the hydrothecne free. 



c Hydrothecal margin sinuous not toothed. D. rosacea. 



cc Hydrothecal margin with three prominences; hydrothectc and gonangia 



very large. 7). famariscn. 



Diphasia fallax (Johnston). 



Trophosome. Stem erect; branching irregular; 

 branches often terminating in long hooked tendrils; 

 hydrothecae almost opposite, short, stout, only a small 

 distal portion free; margin sinuous. 



Gonosome. Gonangia borne in rows on front of 

 branches; male obovate with distal portion quadrangu 

 lar, constricted to a tubular process for the aperture; 

 female gonangia larger, terminating in four, long- 

 pointed lobes; an internal marsupium present. 



No. 80. 

 Diphasia fallax. 



